Tone arm for sound-reproducing instruments



June 26, 1928.

F. W. REED TONE ARM FOR SOUND REPRODUCING NSTRUIENTS Filed May 21, 1925 llllllllll al @eed Patented June 26, 1928.

UNITED STATI-:s

PATENT voFFlce.

Application led Iay 81, 1925. aerial No. 31,818.

relates to improvements in sound amplifiers for sound reproducing instruments, and is particularly adapted to be used in connection wit-h radio receiving sets.

An object of this invention is to provide an improved forml of amplifier which is so constructed as to amplify the sound without distortion,-and that the device may occupy a minimum amount of space.

A further objectmf the invention is to provide an improved amplifier formed of a conduit which has interior diameters gradually increasing from one end to the other, and which is so arranged that the device cannot be easily tipped over.

With the foregoing and other objects in view which will be made manifest in the following detailed pointed out in the appended claims, reference is had to the accompanying drawings `for an illustrative embodiment of the invention, wherein:

Figure 1 is aperspective view of the improved ampliiier or tonefarm,

Fig. 2 is a front elevation of the device, parts being broken away, which may be considered as taken in the direction of the arrow 2u n Fig. 1,.and

ig. 3 is a vertical section through the device taken upon the line 3 3 of Fig. 2.

Referring to the accompanying drawings wherein similar `reference characters designate similar parts throughout, the improved amplifier consists of a base 10, on which is placed the conduit 11. The conduit 11 has interior diameters gradually increasing in size from the end 12 to the other end 13. It is reversely bent upon itself, as indicated at 14, to provide a small portion 15 and a large portion 16', which have their axes substantially parallelv and extending vertically upward from the base 10. As the taper of the conduit 11 is constant throughout, it will be appreciated that the parallel axes of the port-ions 15 and 16 enable the adjacent sides ofthe portions 15 and 16 to be parallel. In the preferred form of construction, a web 17 connects the adjacent sides of the prtions 15 and 16.

The upper end of the portion 15 is laterally bent, as indicated at 18, and is adaptto receive any conventional type of radio unit 19. The upper end of the rtion 16 is forwardl bentand is provide with a bell 20. In t e-preferred form of construction, this bell is rectangular in cross section and is This invention description and specifically preferably formed of wood. It is secured to the portion 15 of the conduit 11 as by screws 21, although in some instances the bell 20 can be formed integral with the conduit 11. In either event, the conduit 11, the reinforcing web 17 and the base 10 are preferably formed of a single integral casting, preferably of aluminum, although other materials can be employed.

By considerable experimentation I have found that an amplification of sound from a radio unit depends upon the size and length of the conduit. The dimensions of the improved form of amplifier therefore play an important part in its construction, as a variation'of size will produce distortion.'` I have found that in order that the amplifier will clearly amplify the sound, the upper end 12 of the portion 15 should have its interior diameter approximately threefquarters of an inch, whereas the upper end 13 of the portion 16 should have its interior diameter substantially three inches. The interior length of the conduit 11 should be substantially twenty-four inches. By making the conduit with such dimensions, an amplification of sound is possible without distortion. Furthermore, if a greater taper or a smaller taper is used upon the conduit, the amplification will be such as will not produce a proper clear tone reproduction of the proper pitch. It will be noted that as both portions 15 and 16 are arranged directly above the center of the base 10, that the center of gravity of the device is substantially over the center of the base, and that the device cannot be easily tipped over. Furthermore. as both porztidns 15 and 16 are arranged vside by side,

ause of the reverse bend 14 being positioned upon the base, the device occupies a relatively small amount of space, but at the same time allows therequired size or length of conduit to be used. i

From the above it. will be appreciated that an improved form of ampllfier or tone arm.

is provided, which is not only so constructed as to occupy a small space, but which will properly amplify sounds from a radio unit and is of an attractive appearance.A

It will be understood that various changes in the detail of construction may be made without departing from the spirit or scope 4of the invention as defined by the appended claims.

I claim:

v1. A devicey of the class described coming an integral casting providing a prising a single casting providing a base, a conduit reversely bent to provide parallel portions and having its bend on the base and itsn two parallel portions extending upwardly therefrom, a web connecting the parallel portions of the conduit, said conduit having its internal diameter gradually increasing froln one end to the other, and means providing a bell upon the enlarged end of the conduit.

2. A -device of the class described comprising a tubular conduit having its interior diameter gradually increasing in size from one end to the other, the conduit being reversely bent upon itself so that the axes ,of the two reversely bent portions of the conduit are substantially parallel, and means providing an integral base for the device at the mentioned bend in the conduit.

3. A device of the class describedcom-l prising a base, a tubular conduit having its interior diameter gradually increasing in size from one end to the other, said conduit being reversely bent upon itself, with the bend positioned upon the base, the portions of the conduit extending upwardly from the base and having their axes substantially parallel, and means providing a laterally extending bell upon the enlarged end of the conduit.

4. A device of the class described vcomprisbase, a reversely bent conduit upon the base with its the portions of the conduit extending upwardly their axes substantially parallel, the interiorof the conduit having diameters gradually increasing in size from one end to the other, and means providing a' laterally extending bell upon the enlarged end of the conduit, the bell extending over the reduced end of the conduit and the reduced end of the conduit having its upper end bent laterally from beneath the bell. y

5. In a device of the class described, a tubular conduit reversely bent `upon itself, the interior of the length being approximately twenty-four inches long, and the interior size of the conduit gradually increasing from approximately three-quarters of an inel in diameter Vat one end to approximately a three inch diameter near the other end.

6. In a device of the class described, a tubular conduit reversely bent upon itself,

the interior-of the length being approxi.

mately twenty-four inches long, and the interior size of the. conduit gradually increasv ing from approximately three-quarters of an inch in diameter at one end to ap roximately a three inchdiameter near the ot er end, and means providing a laterally extending bell upon the large end of the conduit.

In testimony whereof I have signed my name to this specification. i

FRANK W. REED. 

